| 11. |
- Larsson, Pål G., et al.
(author)
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Decrease in Propagation of Interictal Epileptiform Activity After Introduction of Levetiracetam Visualized with Electric Source Imaging
- 2010
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In: Brain Topography. - : Springer Science and Business Media LLC. - 0896-0267 .- 1573-6792. ; 23:3, s. 269-278
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Journal article (peer-reviewed)abstract
- Different neuroimaging techniques (fMRI, spectroscopy, PET) are being used to evaluate candidate drugs in pharmacological development. In patients with epilepsy fast propagation of the epileptiform activity between different brain areas occurs. Electric Source Imaging (ESI), in contrast to the aforementioned techniques, has a millisecond time resolution, allowing visualization of this fast propagation. The purpose of the current project was to use ESI to investigate whether introduction of an antiepileptic drug (levetiracetam, LEV) would change the propagation patterns of the interictal epileptiform activity. Thirty patients with epilepsy were subject to an EEG recording before (pre-LEV) and after (in-LEV) introduction of LEV. Interictal spikes with similar topographic distribution were averaged within each subject, and a distributed source model was used to localize the EEG sources of the epileptiform activity. The temporal development of the activity within 20 regions of interest (ROIs) was determined, and source propagation between different regions was compared between the pre-LEV and in-LEV recordings. Patients with epileptic seizures showed propagation in 22/24 identified spike types in the pre-LEV recordings. In the in-LEV recordings only 7/15 spike types showed propagation, and six of these seven propagating spikes were recorded in patients with poor effect of treatment. Also in patients without seizures LEV tended to suppress propagation. We conclude that the observed suppression of source propagation can be considered as an indicator of effective antiepileptic treatment. ESI might thus become a useful tool in the early clinical evaluation of new candidate drugs in pharmacological development.
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| 12. |
- Larsson, Pål G., et al.
(author)
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Do sleep-deprived EEG recordings reflect spike index as found in full-night EEG recordings?
- 2010
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In: Epilepsy & Behavior. - : Elsevier BV. - 1525-5050 .- 1525-5069. ; 19:3, s. 348-351
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Journal article (peer-reviewed)abstract
- The sleep EEGs of many children with neurodevelopmental disorders reveal epileptiform activity. The aim of this study was to compare spike index (SI) in full-night recordings with SI in sleep-deprived EEGs in the morning; EEGs were obtained over 24 hours using ambulatory equipment. Sixteen children between the ages of 7 and 12 years were included in the study. They had to wake up at 3:00 AM and go to sleep again at 7:30 AM. Epileptiform activity was quantified, and SIs of full-night and morning recordings were compared. Two patients did not fall asleep. In one recording there was a technical problem that made calculations impossible. SIs calculated from EEGs obtained during a short nap in the morning were comparable to those calculated from full-night recordings. There seems to be a higher failure rate during morning recordings because of patients not falling asleep.
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| 13. |
- Mefford, Heather C, et al.
(author)
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Rare copy number variants are an important cause of epileptic encephalopathies
- 2011
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In: Annals of Neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 70:6, s. 974-985
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Journal article (peer-reviewed)abstract
- OBJECTIVE:Rare copy number variants (CNVs)-deletions and duplications-have recently been established as important risk factors for both generalized and focal epilepsies. A systematic assessment of the role of CNVs in epileptic encephalopathies, the most devastating and often etiologically obscure group of epilepsies, has not been performed.METHODS:We evaluated 315 patients with epileptic encephalopathies characterized by epilepsy and progressive cognitive impairment for rare CNVs using a high-density, exon-focused, whole-genome oligonucleotide array.RESULTS:We found that 25 of 315 (7.9%) of our patients carried rare CNVs that may contribute to their phenotype, with at least one-half being clearly or likely pathogenic. We identified 2 patients with overlapping deletions at 7q21 and 2 patients with identical duplications of 16p11.2. In our cohort, large deletions were enriched in affected individuals compared to controls, and 4 patients harbored 2 rare CNVs. We screened 2 novel candidate genes found within the rare CNVs in our cohort but found no mutations in our patients with epileptic encephalopathies. We highlight several additional novel candidate genes located in CNV regions.INTERPRETATION:Our data highlight the significance of rare CNVs in the epileptic encephalopathies, and we suggest that CNV analysis should be considered in the genetic evaluation of these patients. Our findings also highlight novel candidate genes for further study.
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